The present invention relates to electrosurgical probes for treating damaged, diseased or enlarged tissue, and to surgical procedures that make use of such probes.
Electrosurgical effects can be accomplished by applying a highly damped radio frequency (RF) current to tissue through an electrode in the form of an active (+) electrode (tip) of an electrosurgical (electrocautery) probe, from which the RF current flows to a ground (−) electrode. RF electrosurgical probes (RF probes), such as those commonly used in urological and hysteroscopic procedures, are said to be monopolar or bipolar or said to have a monopolar or bipolar operating mode, depending on their electrode configuration. RF probes operating in a monopolar mode utilize a single (active) electrode (tip) and rely on external grounding of a patient (e.g., a ground electrode in the form of a patient plate) to cause current flow from the active electrode to tissue of the patient. RF probes operating in a bipolar mode have two electrodes, typically designated as active and return electrodes, and current flow is localized between these electrodes. As it passes through tissue from the active electrode to the ground or return electrode, the RF current resects (cuts), coagulates and/or ablates (desiccates) the tissue, depending on the type of probe and the RF power and wave length combinations used. RF electrosurgical probes are typically placed through a resectoscope (used in urological procedures), hysteroscope (used in gynecological procedures) or other device, which is often equipped with a telescope so that the active electrode of the probe is in direct view of the surgeon at all times. Irrigating solutions are commonly used as a distention medium and a coolant for the active electrodes of RF probes during electrosurgical procedures.
Resectoscopes and hysteroscopes (hereinafter referred to as electrosurgical probes) have been used for decades to diagnose and treat medical conditions in the human bladder and the uterus, respectively. Electrosurgical resection refers to procedures by which damaged, diseased or enlarged tissue is removed with an electrosurgical probe. A nonlimiting example is transurethral resection of the prostate (TURP), in which prostate tissue is removed by means of an active electrode (for example, a cutting loop) passed through the urethra by means of a resectoscope. This procedure has served as the historical treatment of benign prostate hypertrophy (BPH)), commonly known as “enlarged prostate,” and prostatitus. Bladder tumors and cysts in men and women are also treated by electrosurgical resection. Electrosurgical ablation refers to procedures by which an electrosurgical probe is used to ablate (dessicate) tissue, which eventually sloughs off instead of being immediately removed on contact with the electrode. A nonlimiting example of an electrosurgical ablation procedure is endometrial ablation to treat endometriosis in women, in which tissue is removed by means of roller that serves as the active electrode. Another example is transurethral ablation of the prostate (TUAP), in which prostate tissue is ablated by means of an electrocautery probe passed over a stylet/obturator or guide wire, through the prostatic urethra.
In addition to its electrode, an electrosurgical probe typically includes a working element equipped with a power cord for connection to an RF electrosurgical current generator, and a sheath that extends from the working element and through which one or more conductors are routed to deliver RF current to the electrode protruding from a distal end of the sheath. The probe is also typically equipped with a telescope and/or light source disposed in one or more internal channels within the sheath to allow direct vision during placement and use of the probe. The electrode and its conductor(s) may be capable of reciprocal movement within the sheath through the operation of an actuation lever of the working element. The sheath may also define an internal flow channel to enable an irrigation fluid to be delivered for immersion cooling of the electrode. The RF generator, light source, and telescope are capital equipment and available in a typical surgical suite. While electrosurgical probe electrodes are disposable and therefore do not require sterilization after use, the remaining components of a electrosurgical probe, including the working element, sheath and telescope, are typically formed of stainless steels or another durable metallic material and durable heat-resistant plastics that enable these components to be reused following re-sterilization, for example, using an autoclave and/or ethylene oxide gas. As such, electrosurgical probes typically have high initial purchase costs. The distal end of the sheath is often equipped with a plastic tip that becomes damaged over time, in some cases after a single use, as a result of the high RF current levels, necessitating that the sheath undergo an expensive and time-consuming repair. Also due to the RF currents, metal components of an electrosurgical probe require electrical insulation to protect the surgeon from receiving shocks and burns during use of the probe. Even so, surgeons are commonly required to wear two pairs of latex gloves as a safety precaution.
Sterilization can be a complicated process, particularly in view of the internal channels within the sheath that accommodate a light source, telescope, and/or cooling flow stopcocks and channels. Furthermore, components of reusable electrosurgical probes are conventionally individually reprocessed, sterilized, and packaged, and then kept in drawers, cabinets, and carts accessible to the surgical team. If any of the components are unavailable or the wrong size, the procedure cannot go forward. Generally, hospitals have additional electrosurgical probes on hand in case one fails during surgery. However, at times when case loads are high, a physician may be forced to either wait for another unit to be sterilized or cancel the surgery.
Since the late 1980's, the use of disposable (sterile, one-time use) surgical instruments and devices has dramatically increased in the United States. This trend of cycling from reusable to disposable surgical instruments and devices is taking place now in countries around the world as their economies grow, as is the awareness of the risks and costs associated with hospital-acquired infections, especially those in the operating room. This trend is driven by numerous factors, such as sterility assurance, quality/performance, reducing cross contamination, and cost factors (cost control, convenience, and patient charges).